Design of steep-slope negative-capacitance FinFETs for dense integration: Importance of appropriate ferroelectric capacitance and short-channel effects

摘要

In this study, we investigate the feasibility of steep subthreshold swing (SS) operation in highly scaled FinFETs whose gate length reaches up to 20 nm by harnessing the negative capacitance (NC) of a ferroelectric-gate insulating layer. Our two-dimensional technology computer-aided design simulation reveals that a considerable discrepancy exists between the remnant polarization of a substantial ferroelectric material such as HfO2 and a preferable material to attain a steep SS of less than 60 mV/decade. A considerably smaller remnant polarization of approximately 1.5 mu C/cm(2) is determined to be the key to achieve a steep SS by matching the capacitances of the ferroelectric-gate insulator and the fin channel. The short-channel effects on NC FinFETs with small remnant polarization is also discussed and can be mitigated in the case when the gate length is more than 40 nm by choosing optimum parameters. (C) 2018 The Japan Society of Applied Physics.